Digital video can be transmitted from a source, such as a computer, to a display, such as a video monitor, using a protocol known as Digital Visual Interface (DVI). Having been developed primarily for computers, DVI does not envision processing audio data.
Accordingly, to extend communication protocols to digital multimedia that includes audio for the purpose of, e.g., playing digital movies and the like, a protocol referred to as High Definition Multimedia Interface (HDMI) has been developed. HDMI is similar to DVI except it envisions the use of audio as well as video data and it adds television-related resolutions. Both DVI and HDMI are intended for wired transmission, and HDMI further permits the encryption of digital multimedia using an encryption method known as High-Bandwidth Digital Content Protection (HDCP). DVI also supports HDCP as an optional characteristic.
As recognized herein, to save table space and to increase people's mobility and viewing lines in the room, it may be desirable to view the multimedia on a display using a minimum of wiring. For instance, it may be desirable to mount a projector on the ceiling or to mount a plasma display or liquid crystal high definition (HD) television display on a wall, out of the way and capable of receiving multimedia data for display without the need for wires, since as understood herein among other things data transmission lines often do not exist in ceilings or walls.
The present invention further understands, however, that not just any wireless transmission system will do. Specifically, if a wireless link such as IEEE 802.11(b) is used that has a bandwidth which is insufficient to carry either compressed or uncompressed multimedia such as uncompressed high definition (HD) video, compressed multimedia standard definition (SD) video would have to be transmitted, requiring a relatively expensive decompression module at the projector. Some links such as IEEE 802.11(a) do have a bandwidth high enough to carry compressed HD video but not uncompressed SD or HD video. Also, in the case of 802.11 (a) copyright protection may be implicated because the link is sufficiently long range (extending beyond the room in which it originates) that it can be detected beyond the immediate location of the transmitting laptop. With this in mind, the present invention recognizes the need for a very short range, preferably directional, high bandwidth wireless link that is particularly suited for the short range wireless communication of uncompressed multimedia, particularly the rather voluminous genre of multimedia known as HD video.
In any case, as mentioned above for the HDMI and DVI standards, wireless transmission is not envisioned. The present invention recognizes that to effect wireless short-range transmission of audio and video data, modifying a wireless component to process HDCP-encrypted HDMI, transmit it, and receive it on the other end of the wireless path, prior to sending it on to an HDMI display device, would entail the use of an additional HDMI transmitter and receiver. This in turn would require further licensing of keys, etc. for the added components as well as the use of HDMI components, which can be more expensive than DVI components. Also, because the HDMI wireless components would decrypt the HDCP, transmit the data, and then re-encrypt at the receiving end, the data would be “in the clear” for part of the transmission path and, hence, susceptible to unauthorized intercept.